1. Field of the Invention
The present invention relates to a manufacturing method of an absorbent article, in which a web is folded in two in a direction perpendicular to a conveyance direction of the web.
2. Description of the Related Art
Conventionally, in a manufacturing method of an absorbent article such as a disposable diaper, leg circumferential regions (for example, leg holes) are formed on a web on which individual members (for example, a gather, a waterproof sheet, an absorber, and a top sheet) are laminated. The web on which the leg circumferential regions are formed is folded in two at the center line in a direction (Crossing Direction (CD)) perpendicular to a conveyance direction (Machine Direction (MD)) of the web.
For example, in the folding process of folding the web in two, a first half region on one side divided by the center line in the CD is conveyed between multiple rollers which are arranged at predetermined spacing in the conveyance direction of the web. At this time, a second half region on the other side of the center line in the CD is folded by guide means towards the first half region using a folding center bar as a reference (for example, see Japanese Patent Application Publication No. 2005-46246 (pages 6 and 7, FIGS. 3 and 4)).
However, the above-described manufacturing method of an absorbent article has the following problem. That is, the first half region is conveyed with being partially supported by the multiple rollers which are arranged at predetermined spacing. Therefore, the first half region is suspended in the air at portions between the multiple rollers.
At this time, the crotch region of the web on which a waterproof sheet and an absorber are laminated comes into contact with the guide means or the folding center bar, and therefore conveyance of a crotch region gets behind conveyance of a waistline region. Accordingly, the second half region is sometimes folded towards the first half region with the crotch region being twisted. This damages the appearance of the absorbent article or generates a manufacturing failure of the absorbent article in processes after the folding process.
Furthermore, if the second half region is folded towards the first half region with the crotch region being twisted, the twist affects a portion including the waistline regions and the crotch region in both of the first half region and the second half region. Accordingly, a distortion and a deformation entirely spread over the absorbent article. In particular, the twist affects greatly in the absorbent article having a stretching property. Thus, there is a room for improvements.
Thus, the present invention has been made in light of the foregoing situation. Accordingly, an object of the present invention is to provide a manufacturing method of an absorbent article, which is capable of preventing a manufacturing failure of an absorbent article.